Murmur vs. Bruit?

  1. Can someone explain the difference in sound between a murmur and a bruit? I've had two patients recently who I thought had bruits. But other nurses had charted murmurs. I thought a murmur was a kind of "soft" heart sound--a blurring of the "lub" and "dub." The two patients in question a had distinct, high-pitched, rhythmic "hmmm, hummm, hummm." So what was I hearing????

    THANKS!
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    About GermPhobe

    Joined: Jan '06; Posts: 31; Likes: 13

    7 Comments

  3. by   augigi
    Depends what and where you are listening to?

    A bruit is generally a sound made by a non-cardiac vessel, while a murmur is made by abnormal flow through a cardiac valve (either accelerated by a narrowing, or backflowing through an incompetent valve).

    Hope that helps, tell me if it was too basic.
    Last edit by augigi on Sep 25, '06
  4. by   Indy
    Quote from augigi
    Depends what and where you are listening to?

    A bruit is generally a sound made by a non-cardiac vessel, while a murmur is made by abnormal flow through a cardiac valve (either accelerated by a narrowing, or backflowing through an incompetent valve).

    Hope that helps, tell me if it was too basic.
    A bruit is not usually heard over the part of the chest where you hear heart sounds. It can be heard over the carotids, femoral arteries, A-V fistula sites, etc. A bruit sounds like a washing machine to me. (Ok, a really small washing machine...) A murmur is abnormal noises made by heart valves. So a bruit over the heart would be a... bad thing, since other than the AV fistula, it's not a sound you want to hear in a big vessel. Either something's really blocked the vessel, or there's a pseudoaneurysm going on. Both of which could happen to the aorta near the heart, but golly. I think if I heard that I'd have several other people in there listening just to make sure.

    Hope that helps.

    Woops. Just realized I quoted the wrong post. Eep!
  5. by   GermPhobe
    Quote from augigi
    Depends what and where you are listening to?

    A bruit is generally a sound made by a non-cardiac vessel, while a murmur is made by abnormal flow through a cardiac valve

    Hope that helps, tell me if it was too basic.
    A bit too basic, LOL. I know the physiological difference between the two--but I'm wondering how they sound different. In one case, the "murmur" was so loud it could be heard while I was auscultating bowel sounds! Of course it was INCREDIBLY loud over the heart. But it was NOT a softening of lub-dub. It was simply a very LOUD, pulsatile "hmm, hmm, hmm." I was thinking it could be an aortic aneurysm?

    How LOUD can a murmur get?
  6. by   augigi
    Sorry. The loudness depends on the severity of the underlying pathological condition. That is like asking "how long is a piece of string?" - there is no answer to that. I have definitely heard murmurs which were "whooshing", loud noises and not "clicks".

    Again, as to your initial question, if it is of cardiac origin it's a murmur, no matter how it sounds. An aortic aneurysm doesn't usually cause a loud bruit, as there is generally aortic widening at the weak site, rather than narrowing which would cause the rushing sound caused by acceleration of the blood.
    Last edit by augigi on Sep 26, '06
  7. by   augigi
    PS: What was the patients' history - anything that would support the diagnosis of murmur?
  8. by   GermPhobe
    Yes, he had a known murmur. But, being a new nurse, I'd only heard very quiet murmurs. HOLY COW that one was loud--and sounded like the bruit that was diagnosed on another patient I'd dealt with. Putting two and two together, I concluded this murmur must be "more" than just a murmur. Perhaps I should put the math book away, LOL.
  9. by   augigi
    Don't worry, until you listen to hundreds they all sound like a washing machine in varying states of disrepair!! I used to nod along at nursing school when I couldn't tell what the heck they were hearing cos it sure wasn't what I was hearing!

    I go on the theory that if it's quiet enough that I can hardly work out what it is, it isn't going to be much of a problem for them. Generally when someone is sick from a cardiac condition, there aint no mistaking the presence and type of murmur!

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